ENS 43202
ENS Event | |
|---|---|
19:05 Feb 28, 2007 | |
| Title | Extremely Small Amount of Snm Unaccounted for |
| Event Description | This is a non-emergency event notification in accordance with 10 CFR 20.2201(a)(1)(ii) to report an accountability discrepancy of licensed material.
In the process of reviewing records, it was identified that all disposition records for reactor incore detectors could not be found. The reactor incore detectors contain very small quantities of U-235 and were used to monitor reactor power at Zion Station from 1972 to 1988. The unaccounted for material was classified as missing on February 28, 2007 due to lack of records documenting the current location of the detectors; however, based on available records and discussions with former Zion Nuclear Material Custodians, it is believed that these detectors were shipped as radioactive waste to the Barnwell Low-Level Radioactive Waste Disposal Facility located in South Carolina. A search of storage locations at Zion was performed, but the detectors have not been located. Historical records indicate that it was common practice for Zion Station to dispose of detectors in this manner. There is no evidence of theft or diversion of these detectors. The incomplete records involve 43 incore detectors received onsite prior to 1988. The detectors contain an extremely small amount of Special Nuclear Material and pose no significant safety concern. Depending on design, each incore detector contained between 0.0025 grams to 0.0004 grams of Uranium 235 resulting in an aggregate quantity of approximately 0.102 grams of Uranium 235. The activity of this quantity is approximately 0.22 microcuries. This quantity is greater than the reportability threshold of 10 times the quantity specified in Appendix C to 10 CFR 20 which is 0.01 microcuries. A subsequent written report will be made in accordance with 10 CFR 20.2201(b). The licensee will notify the NRC Resident Inspector and the State. THIS MATERIAL EVENT CONTAINS A "LESS THAN CAT 3" LEVEL OF RADIOACTIVE MATERIAL Sources that are "Less than IAEA Category 3 sources," are either sources that are very unlikely to cause permanent injury to individuals or contain a very small amount of radioactive material that would not cause any permanent injury. Some of these sources, such as moisture density gauges or thickness gauges that are Category 4, the amount of unshielded radioactive material, if not safely managed or securely protected, could possibly - although it is unlikely - temporarily injure someone who handled it or were otherwise in contact with it, or who were close to it for a period of many weeks. This source is not amongst those sources or devices identified by the IAEA Code of Conduct for the Safety & Security of Radioactive Sources to be of concern from a radiological standpoint. Therefore is it being categorized as a less than Category 3 source |
| Where | |
|---|---|
| Zion File:ZionSolutions icon.png Illinois (NRC Region 3) | |
| Reporting | |
| 10 CFR 20.2201(a)(1)(ii) | |
| Time - Person (Reporting Time:+-4.82 h-0.201 days <br />-0.0287 weeks <br />-0.0066 months <br />) | |
| Opened: | Arthur Adams 14:16 Feb 28, 2007 |
| NRC Officer: | John Knoke |
| Last Updated: | Feb 28, 2007 |
| 43202 - NRC Website
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Unit 1 | |
|---|---|
| Reactor critical | Not Critical |
| Scram | No |
| Before | Decommissioned (0 %) |
| After | Decommissioned (0 %) |
Unit 2 | |
|---|---|
| Reactor critical | Not Critical |
| Scram | No |
| Before | Decommissioned (0 %) |
| After | Decommissioned (0 %) |
WEEKMONTHYEARENS 432022007-02-28T19:05:00028 February 2007 19:05:00
[Table view]10 CFR 20.2201(a)(1)(ii) Extremely Small Amount of Snm Unaccounted for 2007-02-28T19:05:00 | |